Refining of steel in electric furnaces.



UNITED STATES PATENT OFFICE.

OTTO THALLNER, OF BISMAROKHIlTTE, GERMANY, ASSIGNOR TO THE FIRM OF BISMARCKHIlTTE, OF BISMAROKHUTTE, GERMANY.

REFINING- OF STEEL IN ELECTRIC FURNACES.

Specification of Letters Patent.

Patented June 22, 1909.

Application filed June 17, 19 8. Serial No. 439,044.

To all whom it may concern:

Be it known that I, O'rro THALLNER, metallurgist, a subject of the German Emperor, and resident of Bismarckhiitte, in the Prov- 'ince of Upper Silesia, German Empire, have invented certain new and useful Improvements in the Refining of Steel in Electric Furnaces, of which the following is an exact specification.

This invention relates to the refining of steel in electric furnaces.

In my copendingrapplication Serial No.

439043 filed 17th June 1908 I have described a process of refining steel in which the steel, preferably previously refined in a fuel heat-- ed furnace, is passed to an electric furnace for the purpose of efiecting a higher degree of refinement and allowed to settle in a crucible having an acid lining material. Instead of employing a crucible, according to the present invention I employ an electric furnace lined with an acid lining such as a lining in which the principal ingredient is silicic acid. I I

In carrying the present process into effect the steel, preferably previously refined in: a Martin- Bessemer or Thomas furnace, is treated inan electric furnace provided with a basic-lining such as lime. In this furnace the refining is carried out to ahi h extentuntil the metal is perfectly free 0111 carbon, manganese, silicon, phosphorus and sulfur. In this condition the metal contains 'not only considerable 'quantities of oxygen 35 in the.form of oxids but it possesses also. the capability of takin up oxygen whencomingin contact with the air during pouring. This unfavorable property can be avoided by carrying out the last stage of the process on an acid hearth. This end process that is the treatment in the acid'lined electric'furnace comprises removal of the oxids contained in the bath owing to the action of the acid hearth and then carbonization. Also the addition of alloys can take place in the acid electric furnace much more favorably than in a basic lined furnace. Such addition may be for example. silicon, chromium, Wolfram or nickel. By means of this combination of acid and basic electric furnaces it is possible to produce a product which possesses a perfectly com act structure with only the smallest possi le content of manganese and carbon or with practically none of these constituents. The material to be treated can be run from one furnace to the other or can be carried over in suitable P I I claim;

1 .'A process for re the steps of refinin the steel to a-high extent in a basic lined eectric furnace and then treating the same in an acid lined electric furnace, substantially as described.

fining steel comprising 2. The rocess for producing. high quality 6 steel consi ting in preliminarily refining the steel in afuel heated furnace, then passing the steel so refined for treatment in a basic lined electric Qfurnace, after which the steel is passed'to an'acid lined electric furnace for the purpose set'forth.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

oT'ro THALLNE-R.

Witnesses:

' Enns'r KARL,

Elmer KATZ. 

